Re: [Qemu-block] [PATCH] block.c: fix real cdrom detection

[Stefan Hajnoczi]

On Tue, Jun 23, 2015 at 02:26:51PM -0400, Programmingkid wrote:
> 
> On Jun 23, 2015, at 2:06 PM, John Snow wrote:
> 
> > 
> > 
> > On 06/23/2015 01:56 PM, Programmingkid wrote:
> >> Fix real cdrom detection so that a real cdrom can actually be used.
> >> 
> >> signed-off-by: John Arbuckle <address@hidden
> >> <mailto:address@hidden>>
> >> 
> >> This patch has been tested on Mac OS X host and guest. 
> >> Command used: qemu-system-ppc -cdrom /dev/cdrom
> >> 
> >> Note: I was able to view the files using OpenBIOS, but not on 
> >> Mac OS X. The size of the disc is reported correctly but some
> >> error happens that prevents it from mounting in Mac OS X. This
> >> is probably another bug with QEMU.
> >> 
> >> ---
> >> block.c |    3 ++-
> >> 1 files changed, 2 insertions(+), 1 deletions(-)
> >> 
> >> diff --git a/block.c b/block.c
> >> index dd4f58d..75ccfad 100644
> >> --- a/block.c
> >> +++ b/block.c
> >> @@ -583,7 +583,8 @@ static int find_image_format(BlockDriverState *bs,
> >> const char *filename,
> >>     int ret = 0;
> >> 
> >> 
> >> 
> >>     /* Return the raw BlockDriver * to scsi-generic devices or empty
> >> drives */
> >> -    if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
> >> +    if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0 
> >> +               || strcmp("/dev/cdrom", filename) == 0) {
> >>         *pdrv = &bdrv_raw;
> >>         return ret;
> >>     }
> >> -- 
> >> 1.7.5.4
> >> 
> > 
> > So what's the issue that this patch attempts to fix and how did you
> > determine that the fix was needed here? It doesn't look like it respects
> > proper abstraction at a glance.
> 
> Without the patch, QEMU would just quit when the "-cdrom /dev/cdrom" option 
> is given.

Why does it quit?

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